UN I need to talk

As the UN prepare for crisis talks in South Africa, Emma Summerscales fills us in on the often overlooked realities of climate change

That person you can see deep in thought sat on the metro or in the café probably isn’t thinking about climate change. There’s no denying it’s a daunting issue, but really when you turn the lights off, or complain that your housemate keeps putting the heating on and not wearing a jumper, you’re thinking of the bills and not the polar bears. Everyone knows it’s a potentially devastating problem that we need to try and reign in. Surely though, we can sleep easy knowing that someone somewhere is tackling the problem?

Probably not. We are far from understanding all the complex processes that come together to affect the global climate, and the process of change that we are currently seeing is unprecedented. It is common knowledge that the earth is getting warmer because of greenhouse gas emissions, and that this will cause a rise in sea levels. Everyone probably knows at least one of those guys who quip that climate change is a product of the earth’s natural cycle (whatever that is). Though this is a good starting point, the whole process is far more complex. So what is actually happening with regards to the changes in our planet’s climate? It is a question that can only be answered as far as our current knowledge takes us; in that spirit it is perhaps more objective to ask what we don’t know.

Britain is an island, at the mercy of the Atlantic ocean. It is of paramount concern that one of the most discussed impacts of a warmer planet is rising sea levels. While we all needn’t fashion a makeshift life raft just yet, the threat is tangible, and very real.

The glaciers, ice caps and vast ice sheets of Antarctica and Greenland have the capacity to melt into our oceans. Ice sheets defrost and re-freeze seasonally, however the imbalance has been a little more year upon year. Worrying then, that there is so

Greenhouse gases

By definition these are gases that trap the heat trying to escape from the earth’s surface. This heat is generated when the earth absorbs sunlight, heats up and then emits infra red (IR) radiation (or heat). The gas molecules trap the heat because they have the ability to absorb the IR, vibrate and eventually emit the radiation again. Thus, they share this heat energy with their neighbours, generating a sort of heat-sharing blanket. The biggest offenders are naturally occurring constituents of atmosphere, the much maligned carbon dioxide, water vapour, methane, nitrous oxides and ozone. We never really hear much about the names on that list bar our obsession with carbon, which is surprising when you consider that water vapour is a far more potent greenhouse gas than carbon dioxide.

The problem is relative, and it’s quantitative. Carbon dioxide is the most abundant greenhouse gas, artificially generated in ever-increasing and significant quantities. According to the Intergovernmental Panel on Climate Change (IPCC) the amount of carbon dioxide generated from burning fossil fuels has increased by more than 40% since 1990, and the rate is accelerating.

Carbon sinks

Worryingly, about half the Earth’s seas, which have been behaving as carbon sinks, are at saturation point and could even emit carbon dioxide in the future if sea temperature continues to rise. This could very rapidly exacerbate the situation to an unimaginable point.

Methane sinks, in addition to carbon sinks, are also threatening to emit stored gas in the biggest and most tumultuous fart witnessed since the extinction of the Brachiosaur. Demand for food and increased agriculture has caused a rapid increase in atmospheric methane in recent years, and increasing temperatures threaten to imminently liberate permafrost and oceanic hydrates.

Unfortunately no one knows how high the level of greenhouse gases in the atmosphere will rise, or how hot this means out planet will get. When it comes to planning for the future we are digging around in the dark. Every action has an equal and opposite reaction, so we are probably in for something gargantuan.

Global dimming

As well as gases that warm our planet, there are some pollutants such as aerosols that become incorporated into clouds and reflect the sun’s light away from our planet before it ever has chance to be absorbed and emitted as heat. This is known as ‘global dimming.’ Surely then, this is good news?

Alarmingly, there is a large voice behind the idea that the global temperature rise of just 0.6 degrees is so small because temperature increases have been offset by global dimming, and that disturbingly this could mean the atmosphere is far more sensitive to greenhouse gases than previously thought. The solution isn’t, however, to continually pump dimming pollutants into the atmosphere; global dimming has been blamed for crop failures and years without summers in some parts of the world.

What happens next?

Coastal regions and islands are both attractive and profitable regions to live in and no less than 160 million people live less than one metre above sea level, according to the IPCC. With so many factors involved, each of them incredibly variable, it’s impossible to predict how fast sea levels will rise; spare a thought to one of the 160 million the next time you fall asleep and leave your laptop on all night.

Before we ever reached the disastrous point and we all talked about how much we used to like London, Norfolk, Venice and all of the Netherlands, changes in volume and salinity across our oceans could upset currents, which in turn could negatively impact many established weather patterns. Anyone seen the Day After Tomorrow?

Floods, droughts and storms – dubbed ‘extreme events’ – would become more frequent and intense. Hurricanes form over warm tropical seas, so a rising sea temperature is bad news. Increased temperatures would also change rainfall patterns enormously. Last year’s dry spell and disastrous heatwave in Russia sparked both huge fires and debate overt  whether they were directly linked to athropogenic climate change. How long before we are having similar debates in the UK?

Tipping points

As ominous as their name prerequisites, they are defined as irreversible and abrupt changes in our climate. One day we may reach a certain threshold where our systems can no longer cope and undergo a sudden catastrophic change. There are nine such possible future tipping points highlighted in the last IPCC report, and they include the Amazon rainforest dying and becoming savannah, the end of the Indian monsoon season, and the Greenland Ice Sheet irreversibly shrinking. The very real concept of tipping points highlights the potential power of climate change and how it could change our lives forever. If ice sheets do suddenly start to melt, will they form again if we reduce our emissions dramatically and temperatures go back down? Will sea levels and rainfall decrease again, so that floods plague populations no more?

We don’t know how hot, how cool, how high, how frequent; most importantly, all this means we don’t know what the threat to life is. There remains one certainty, anthropogenic activities are causing raised temperatures and therefore climate change. How this is to be stopped is a matter of debate and international argument, maybe the next weeks talk will ring some changes, but don’t be too hopeful.

We may not know what is going to happen in the future, but from looking at what we do know today it should be said that there has to be something in forgetting our quarrels and pulling together to reduce our carbon footprints. The hustle and bustle can make us flippant, but it is in our power to reduce emissions and stave off tipping points – perhaps forever.